This relates generally to imaging devices, and more particularly, to imaging devices with column circuitry.
Image sensors are commonly used in electronic devices such as cellular telephones, cameras, and computers to capture images. In a typical arrangement, an electronic device is provided with an array of image pixels arranged in pixel rows and pixel columns. Circuitry is commonly coupled to each pixel column for reading out image signals from the image pixels. In a typical image sensor, the column readout circuitry that is coupled to all of the pixel columns in a pixel array is typically powered on.
In some situations, however, only a portion of the image pixels a pixel array may used to capture image data at any given time. For example, in some situations a sub-array of image pixels may be used to capture image data when it is desired to capture image frames having a reduced size at an increased frame rate. In a conventional image sensor, power that could otherwise be used to operate other portions of the imaging system or that could otherwise be stored and used for later imaging operations can therefore be used to unnecessarily power column readout circuits that are coupled to unused image pixels. It can be particularly useful to conserve this type of power in portable imaging systems that use batteries to provide power to the device or in power-saving modes in larger electronic devices with imaging systems.
It would therefore be desirable to be able to provide imaging devices with improved column circuitry.